During the last few years the Drosophila community has begun to realize that it needs an integrated genome program. While the polytene chromosomes have provided a 50-100 kb scale cytogenetic map of the euchromatin for more that 50 years, a true physical map and ultimately the complete genome sequence will be required as workers increasingly exploit Drosophila to understand gene function. The Drosophila Genome Center described in this proposal would establish an integrated program that will focus initially on building a physical map with about 20 kb resolution. Such a map would permit any investigator to identify genomic regions of interest that are represented in any convenient cloning vector. Perhaps of greatest significance, the strategy will use known genes and lethal P element insertions to integrate the physical and genetic maps. Thus the Drosophila physical map that we will construct will provide users not only with access to gene location and ultimately sequence, but to the genetic tools required to analyze gene function and the informatics base for interpreting the results of the large scale DNA sequence studies of the future. In order to best meet the needs of the community, the map will: (1) facilitate cloned access to any and all portions of the euchromatic genome, (2) be closely correlated with both the genetic and polytene chromosome maps, and (3) serve as an efficient substrate for large-scale genomic sequencing. In this way the utility of the physical map will be maximized, even as it is being created. This proposal is based on our belief that a map with these characteristics can best be accomplished by using a Sequence Tagged Site (STS) content mapping strategy. We will determine the overlaps between the cloned inserts of 5-hit Drosophila genomic library that has already been constructed in the bacteriophage P1 (pacmid) vector. Concurrently we will increase the resolution of the map as well as its genetic and biological information content by mapping: (1) about 1000 P element transposition sites that each define a unique vital gene, (2) about 2000 cDNAs that define distinct transcription units, and (3) about 700 known cloned genes. Bringing these resources together into the common framework of a genome map will provide the Drosophila community with a wealth of novel research opportunities and reagents.